SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57da170b8c95c3c413417536ea27a63fde2a96eb146dbb2754044a24d6921f5d' 
  AND token = '0Zm998hTzR/ULuKlLClPkAXR7nhdPC4z8zCYoXJ4jLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}